In nokia terms BCF is Base control function. It is logical identification number of a any cell site as BSC sees it software point of view. When you want to creat new site in BSC database or modify the site parameters in BSC database these modifications are done with ref to BCF number of that cell site.
LAPD is Link access protocol on D channel. It is a GSM layer 2 protocol defined to fascilate signaling between BSC and TRX in the BTS.When you define a signaling for perticular TRX in BTS via mapping it is nothing but LAPD for that TRX.